mcnaug-hton



(No Model.) I

D. C. MGNAUGHTON.

J DENTAL CAST. No. 536,227. Patented Mar. 26,1895.

IN l/E N TOR gWau/ ATTORNEY UNITED I. STATES PATENT OFFICE.

DANIEL O. MCNAUGHTON, OF JERSEY CITY, NEW JERSEY, ASSIGNOR TO THE ASSOCIATED DENTISTS COMPANY, OF SAME PLACE.

DENTAL CAST.

SPECIFICATION forming part of Letters Patent No. 536,227, dated March 26, 1895. Application filed July 18, 1894. Serial No. 517,953. (No model.)

To all whom, it may concern:

Beit known that I, DANIEL C. MONAUGH- TON, a citizen of the United States, residing at .the city of Jersey City, in the count yof Hudson and State of New Jersey, have invented new and useful Improvements in Dental Casts, of which the following is a specification.

In the art of making artificial teeth it is customary to take an impression of the patients mouth in wax or other suitable substance, and from this to make a cast by filling in this impression with plaster. Heretofore, owing to the fragile nature of the plaster, it has always beennecessary to make the bottom of this cast very thick to insure sufficient strength to enable it to be operated upon while in the articulator without danger of breaking. After the removal of the cast from the articulator, it is placed in the vulcanizing flask. Before, however, it can be placed in thisflask, it is necessary to properly fit it by cutting down the sides and bottom. This cutting down so weakens the cast that it frequently happens, that, owing to imperfect drying of the plaster,o'r to its brittle nature when dried, the palate or centerof the cast gives way, when a considerable pressure is applied, as is necessary while packing the cast in the'vulcanizer, and so renders it useless. 1

The objects of my invention are to strengthen dental casts; to do away with the risk'of loss of time and ofbreakage,when under pressure in the vulcanizing flask; to efiect a saving of material; to render the cast 'safe from danger ofbreakage while being handled, particularly in the articulator; and'to entirely do away with the cutting down process formerly necessary to prepare it for the vulcanizing flask. v

To this end my invention consists in combining with the plaster, or other suitable substance to be cast, a reinforcing piece, as is seen by reference-to the accompanying drawings.

Figure 1 is a top view of the reinforcein this instance a metal plate. Fig. 2 is a side view of the same in perspective. Fig. 3 is a side view of a reinforced dental cast.

Similar numerals of reference refer to similar parts throughout the several figures.

1,1 are the bent-up frontal edges'of the plate. 2, 2 are the rear edges similarly bent 3, 3, 3 are the perforations in the plate also with bent-up edges. 4, 4, 4 is the plaster portion of the cast. e

To carry out my invention I'prefer tomake the reinforce in the form of a metallic plate, approximately of thesize and general shape of the mouth to be fitted. This metallic plate in its preferred form I make either with marginal flanges 'overlocking the plastic material of the cast, or with interior flanges struck up from the bottom of the plate, thereby producing perforations in the plate, the walls of which together with the struck up flanges in terlock with the plastic material of the cast, or with both marginal and interior flanges. The interlocking of the reinforce with the plastic material of the cast may also be effected by giving the reinforce a serrated or roughened face or otherwise preparing the plate to cause the plastic material to adhere thereto, preferably under pressure. The object being tosecure a firm upion between the plate and the plastic substance, the manner of accomplishing this result is immaterial.

To further carry out my invention it is only necessary to cover the impression to be filled with the plaster to the thickness of about an eighth of an inch at the center, and immediately upon this, while plastic, to press the reinforce, the plaster being applied evenly forcing plate provided with flanges over-locking or interlocking with the plastic material of the cast, substantially as described.

In testimony whereof I aflix my signature in the presence of two witnesses.

DANIEL C. MCNAUGHTON.

Witnesses:

SEWARD DAVIS, E. Y. Hoon. 

